FWIW, the "Washburn PRO" engraved-style plate is what I have on the Bantam BT-3 & BT-6 next to me, so in use at least ~1996-2000. The previous plates were that "cast look" style. The Bantams came after the Mercurys, with the remaining Mercury line cancelled 1996.

In any case, still very unlikely that anyone sane is going to counterfeit a mid-range 1990s import.